I had this come up recently for a new client I was setting up a new Google Ad Campaign for. They had a Squarespace site and naturally, we wanted to track form submissions as a conversion in the Google Ad Campaign.You can create a separate 'thank you' page and have the form redirect to that page after submission.

You then track pageviews for this 'thank you' page as a conversion using the Google Ad Conversion Tag or setting up a Google Analytics Goal then importing that into Google Ads to track as a conversion. This is perfectly fine and it's a fairly normal setup.

If for whatever reason the client doesn't want them sent to a 'thank you' page. You can also setup form submission conversion tracking using Google Tag Manager. I outline this process in this other blog post here.

You can also track clicks on the form submit button as a conversion as well. It's pretty easy to set this up using Google Tag Manager. I go into more detail about it in another blog post, check it out over here!